Severe Help Needed

I have a 1990 Plymouth Laser and am in desperate need of some help or advice. The car just does not want to work and no one can figure out why. It will only run if you keep your foot constantly on the gas; I have to left-brake it and put it in Neutral whilst driving so it doesn't die. It surges and bucks a lot while it's driving. If anyone could help me figure out what this problem is, I would be very appreciattive.
Thanks in advance!!

How is the tune up on this vehicle. If it is good, start looking for a vacuum leak around the tbi unit. Most of the time one of the hoses will pop off or will split/crack. Follow the pcv hose especially and make sure it is not split. The best way to find a vacuum leak is to let a buddy run the car while you listen for a hissing sound. Good luck.

It is a bit unclear of what is actually happening. Does it only die when you put it into gear? Will it run in neutral at all? Will it run in park?

If so, you are loosing vaccuum. Check all your hoses first. Ensure you have all the bolts that hold the carb on in place.

I have an 86 horizon. If I started the engine and let it sit in park it would run rough. When I put it into gear it would die. The friend I had helping me decided to leave one of the mounting bolts off the carb. This left a big vaccuum leak. After putting the bolt in I was able to get it into gear without dying. This does NOT mean you have this exact problem, what it means is that you may have vaccuum leak somewhere.

If the engine dies no matter what, I would look at the carb and the fuel filters. Check your basics. Check your plugs, wires, distributor, air filter, etc.

More the likely you are just loosing vaccuum. I didn't think this was a big deal overall until I experienced it. Remember though, sometimes you have to get your hands dirty and just look under the hood daily and observe things. I found my last two problems by just looking at the engine every day after starting it.